Battery Thermal Runaway Evaluation Using Nondestructive State Estimation
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Solution Overview
Problem
Existing technologies face challenges in nondestructively evaluating the thermal runaway temperature of secondary batteries, which is crucial for ensuring safety and preventing spreading fires in assembled battery systems.
Innovation Solution
A battery safety evaluation apparatus that includes a battery characteristic estimator, a heat amount estimator, and an end-point cell temperature estimator. This apparatus estimates inner state parameters and battery characteristics based on voltage and current data, calculates the heat amount and safety index of the battery, and evaluates its safety nondestructively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal runaway temperature and heat amount are measured through destructive testing, then measurement precision is improved, but the battery is destroyed and cannot be used again
Solution Approach 1:
The patent creates a virtual copy of the battery's thermal behavior through mathematical modeling. The estimation apparatus uses equivalent circuit models and thermal models to simulate thermal runaway characteristics without physically testing the battery, thereby obtaining precise measurement data while preserving the battery for continued use.
Solution Approach 2:
The patent replaces physical destructive testing with computational estimation. Instead of subjecting the battery to actual thermal runaway conditions that would destroy it, the system uses electrical measurements combined with mathematical models to estimate thermal runaway temperature and heat amount, substituting mechanical/thermal destruction with computational analysis.
2Reliability
If safety devices are added to prevent cell firing, then safety is improved, but device complexity increases
Solution Approach 1:
The patent enables the battery system to self-evaluate its safety status through monitoring and estimation functions. The system continuously assesses thermal runaway risk by analyzing voltage, current, and temperature data through mathematical models, allowing the battery to self-diagnose safety conditions without requiring additional complex safety devices.
Solution Approach 2:
The patent implements a feedback mechanism where the estimation results are used to control battery charging and discharging operations. The system adjusts charging current based on estimated thermal runaway risk, creating a closed-loop safety control that prevents thermal runaway without requiring multiple passive safety devices.
3Measurement precision
If thermal runaway resistance is evaluated through physical testing, then measurement accuracy is improved, but productivity decreases due to battery destruction
Solution Approach 1:
The patent uses virtual modeling to replicate thermal runaway behavior without physical testing. By creating mathematical representations of battery thermal characteristics and using these to estimate thermal runaway parameters, the system achieves accurate evaluation while avoiding the time-consuming and destructive nature of physical thermal runaway tests.
Solution Approach 2:
The patent performs safety evaluation during normal battery operation rather than requiring separate dedicated testing. The estimation apparatus continuously monitors battery state and evaluates thermal runaway risk in real-time, eliminating the need for separate productivity-reducing test procedures.
Data Source
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AI summary
A battery safety evaluation apparatus according to one aspect of the present invention includes a battery characteristic estimator, a heat amount estimator and safety index calculator. The battery characteristic estimator estimates an estimation value of an inner state parameter of a first battery on the basis of data on voltage and current of the first battery measured in charging or discharging. The heat amount estimator estimates a heat amount of the first battery upon change of an external temperature on the basis of first reference data which is at least indicating relationship between a heat amount of a secondary battery and the external temperature and is set to correspond to the first battery on the basis of the estimation value. The safety index calculator calculates a safety index regarding a temperature of the first battery upon change of the external temperature on the basis of the estimated heat amount.